34株致犊牛腹泻的大肠杆菌耐药性分析及合理用药建议

发布时间：2019-03-09 17:24

【摘要】：犊牛腹泻大肠杆菌病是由产肠毒素大肠杆菌所引起的,常常会导致犊牛剧烈腹泻甚至死亡的一种犊牛腹泻病,为奶牛业带来了巨大的经济损失,同时也对人类的健康造成很大的威胁。临床上滥用抗生素的现象越来越严重,导致耐药菌株的增多以及耐药谱的增宽,很多常用抗生素基本已经完全失去效果。因此对全国各地的犊牛腹泻大肠杆菌耐药情况的调查分析,对预防和控制犊牛腹泻病具有重要的意义。本研究主要包括大肠杆菌耐药情况的调查和相关耐药基因的检测两个部分。采用Kirby-Bauer纸片法,对分离自中国北方部分规模化奶牛场的34株犊牛腹泻大肠杆菌对22种常用抗生素的耐药情况和多重耐药进行了分析。结果为34株犊牛腹泻大肠杆菌对强力霉素的耐药率均达到了100%,耐药率在80%以上的有5种,分别为氨苄西林、链霉素、阿奇霉素、强力霉素、复方新诺明。对呋喃妥因、头孢塞肟、多粘菌素B的敏感率均在50%以上,对磷霉素的敏感率达到97.06%,因此对磷霉素最为敏感。本研究通过PCR方法对喹诺酮类、氨基糖苷类、β内酰胺类、四环素类、氯霉素类、磺胺类的相关耐药基因进行检测。喹诺酮类检测了GyrA、GyrB和ParC基因,其扩增阳性检出率分别为70.59%、67.65%、61.76%,27株对喹诺酮类产生耐药性,其中三种基因的阳性检出率分别为74.07%、81.48%、66.67%。氨基糖苷类检测了aadA、aadB和Aph(3’)-II基因,其扩增阳性检出率分别为44.12%、23.53%、61.76%,33株对氨基糖苷类产生耐药性,其中三种基因的阳性检出率分别为42.42%、24.24%、72.72%,其中有一株对氨基糖苷类类没有表现出耐药表型的菌株检出了aadA基因。β内酰胺类检测了blaTEM基因,其阳性检出率为61.76%。氯霉素类检测了floR、cat基因,其阳性检出率分别为52.94%、32.35%,34株大肠杆菌中同时携带这两种基因的检出率为11.76%。磺胺类检测了sul2、sul3基因,其阳性检出率分别为52.94%、70.59%。四环素类检测了tet(B)、tet(D)基因,其阳性检出率分别为35.29%、26.47%。基于以上检测结果,北方部分奶牛场的犊牛腹泻大肠杆菌大部分地区已经产生了严重的耐药性,并且已经检测了其相关的耐药基因,同时试验也证实了耐药基因的传播与扩散导致耐药菌株数的上升,多重耐药菌株的不可遏制给临床治疗带来了很大的困难,本研究为北方地区临床选择药物及如何合理使用抗生素提供了一定的依据。
[Abstract]:Calf diarrhoea colibacillosis is caused by enterotoxigenic Escherichia coli, which often leads to severe diarrhea and even death in calves. It has brought huge economic losses to the dairy industry. At the same time, it also poses a great threat to human health. The abuse of antibiotics in clinic is becoming more and more serious, which leads to the increase of drug-resistant strains and the widening of drug-resistance spectrum. Many commonly used antibiotics have lost their effect completely. Therefore, it is of great significance to investigate and analyze the drug resistance of Escherichia coli in calf diarrhea in different parts of the country in order to prevent and control calf diarrhoea. This study mainly includes two parts: the investigation of drug resistance of Escherichia coli and the detection of related drug resistance genes. The resistance and multi-drug resistance of 34 strains of diarrhea Escherichia coli isolated from large-scale dairy farms in northern China to 22 common antibiotics were analyzed by Kirby-Bauer paper method. The results showed that the resistance rate of 34 strains of Escherichia coli to doxycycline was 100%, and the drug resistance rate was more than 80%. They were ampicillin, streptomycin, azithromycin, doxycycline and compound Xinomin. The sensitive rates to furantoin, cefoxime and polymyxin B were all more than 50% and 97.06% to fosfomycin, so they were most sensitive to fosfomycin. In this study, quinolones, aminoglycosides, beta lactams, tetracyclines, chloramphenicol and sulfonamides were detected by PCR. The positive rates of GyrA,GyrB and ParC genes were 70.59%, 67.65%, 61.76%, respectively, and 27 strains were resistant to quinolones, among which the positive rates of three genes were 74.07%, and the positive rates were 70.59%, 67.65%, 61.76%, 74.07%, respectively. 81.48%, 66.67%. The positive rates of aadA,aadB and Aph (3')-II genes were 44.12%, 23.53%, 61.76%, respectively. 33 strains were resistant to aminoglycosides. The positive rates of three genes were 42.42%, 24.24% and 72.72%, respectively. Among them, one strain with no resistant phenotype to aminoglycosides detected the aadA gene, and 尾-lactams detected the blaTEM gene. The positive rate was 61.76%. The positive rate of floR,cat gene was 52.94%, 32.35% in chloramphenicol group and 11.76% in 34 strains of Escherichia coli, respectively. The positive rate of sul2,sul3 gene was 52.94% and 70.59% respectively. Tetracycline detected tet (B), tet (D) gene, the positive rates were 35.29% and 26.47%, respectively. Based on the above results, Escherichia coli from calf diarrhea in some dairy farms in the north has developed severe drug resistance in most areas, and its related drug resistance genes have been detected. At the same time, the experiment also confirmed that the spread and diffusion of drug-resistant genes led to the increase in the number of drug-resistant strains, and the uncontainment of multi-drug-resistant strains brought great difficulties to clinical treatment. This study provides a certain basis for clinical choice of drugs and rational use of antibiotics in northern China.
【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S858.23

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